By far my worst interviewing experience.
I applied online and had a quick 15 minutes call with HR. Then, I had a first coding round of one hour, two easy/medium Leetcode questions. After that, I had to do a homework. I spent a long time on it to deliver something that was (imo) good, at least correct as it met all the requirements. I submitted my project and simply received an email telling me that I didn't make it to the next round. No feedback in the email, I asked for some and didn't get any response.
Clearly my worst interviewing experience. I don't mind being refused, I just think that they could have a bit of consideration for candidates spending time to apply and not simply send an automated email to reject them.